Nov 26, 2008 · The Jeep 4.0 liter PowerTech Straight-Six engine provided exciting acceleration in Jeep Wranglers for years, with excellent torque. In the Cherokee it did well, in the Grand Cherokee it was a bit sluggish due to the weight of that vehicle.. Sep 30, 2014 · 4.0L jeep crank main bearing removal,4.0L bad piston,motor tear down,high miles,rebuild motor, - Duration: 6:05. View This video 6,676 views. Jul 30, 2012 · The 4.0L was a strong performing engine, no doubt. There were a couple of issues with the basic design, including leaks; the oil pump was notorious for wearing out at around 145,000 to 155,000 miles, and the TPS (throttle position sensor) on the 1989/1990 models would fail if someone spit on the sidewalk..

Sep 08, 2014 · Hey guys n gals, I having an engine swap done in my 1997 TJ. Had a 97 2.5L 4cyl, now getting a 98 4.0L 6 cyl. HOWEVER the wiring harnesses wont mate. Dec 11, 2006 · Wow, I guess the engine was running like crap for awhile because it feels like I'm driving a new Jeep now that I've replaced the wires, dist, and rotor. It had gotten really bad over the last few days, but must have been going downhill for awhile without me really noticing.. ® Inline Six Cylinder Ignition Upgrades The last AMC six was the 4.0L Jeep engine, which served through the 2006 TJ Wrangler. At left, a wiring diagram for the micro.